In the Solar-1 trial in hormone receptor positive, HER2 negative advanced breast cancer patients, patients with PIK3CA mutated tumors who received the PI3K inhibitor alpelisib in combination with fulvestrant had significantly improved progression free survival compared to patients who received fulvestrant alone (11 months vs. 5.7 months; p = 0.00065) [36]. Here, ERBB2 is linked to breast cancer.